This is a nationalization of PCT/GB00/02548 filed Jul. 10, 2000 and published in English.
The present invention relates to a process for the polymerisation of olefins, novel polymerisable olefins, curable compositions thereof, the products thereof and their use in the preparation of shaped products, coatings and the like. More particularly the invention relates to a process for the copolymerisation of monofunctional and bifunctional strained bicyclic olefin monomers, novel monofunctional and bifunctional strained bicyclic olefin monomers, and their associated compositions, products and uses.
The polymerisation of dicyclopentadiene (DCPD) has long been known and commercially operated for the production of shaped thermoset cross linked products which are extremely bard. The products are particularly useful since they undergo surface oxidation allowing them to be painted, and rendering them odorless. The catalysts employed are air sensitive and functional group sensitive, complicating the process, and limiting the reaction in terms of monomer variation.
Polymerisation of derivatives is known from the literature. In particular a number of publications (Ciba Geigy) relate to novel (xe2x80x9cGrubbsxe2x80x9d) catalysts for use in polymerising strained olefins and their derivatives. The catalysts are disclosed as suited for the polymerisation of a vast range of polymerisable monofunctional monomers and difunctional bridged monomers, by virtue of their excellent moisture tolerance. However polymerisation of only a limited number of the disclosed monomer and dimer classes is described. WO 97/38036 describes ring opening metathesis polymerisation of an at least 3 membered alicyclic cycloolefin with a specific ruthenium catalyst. Cycloolefin ring substituents are inert and do not adversely affect the chemical and thermal stability of the catalyst. WO 96/20235 describes the corresponding polymerisation of dicyclopentadiene (DCPD) optionally with an at least 3 membered alicyclic cycloolefin. WO 96/16008 describes the corresponding polymerisation of a bridged cycloolefin as a dimer, trimer or the like.
We have now surprisingly found that by selection of particular classes of novel and known polymerisable monofunctional monomers and difunctional bridged monomers and combinations thereof, and polymerising with a class of transition metal catalyst, a novel type of product may be obtained which exhibits excellent properties in terms of controlling cross-linking density, and associated product modulus and glass transition temperature (Tg), allowing novel uses as elastomers, plastics and composites. Particularly advantageous performance is obtained with use of the known xe2x80x9cGrubbsxe2x80x9d catalysts.
In its broadest aspect the present invention provides a process for the catalytic copolymerisation of strained (poly)cyclic olefins substituted by at least one carbon skeletal group, wherein the olefins comprise a monofunctional monomer and a difunctional monomer.
Accordingly there is provided according to the present invention a process for the catalytic copolymerisation of strained activated cyclic olefins comprising contacting a strained mono (poly)cyclic olefin monomer of formula 
with at least 1 wt % of a strained di (poly)cyclic olefin monomer of formula 
in the presence of a catalyst or an initiating agent wherein the group 
represents a strained (poly)cyclic olefin, tail Y and spacer X comprise preferably electron withdrawing and property modulating groups
whereby the monomers form a copolymer comprising the repeating unit 
and at least 1 wt % of the unit 
which is adapted for subsequent cross linking of respective copolymer chains in the presence of heat and catalyst to form an amount of a cross linked copolymer comprising the unit, 
wherein groups are as hereinbefore defined.
The process of the invention provides for preparation of polymeric materials having tailored properties, whereby monofunctional monomer tail Y and difunctional monomer spacer X may be selected to have desired properties in terms of stiffness or flexibility, mobility or immobility, in terms of tail or spacer length. spatial orientation, and may be combined in any given ratio of monomers and the like.
Without being limited to this theory it is thought that the strained (poly)cyclic olefins of the invention may in fact be substituted by any nature of substituent which allows variation in xe2x80x9csoftnessxe2x80x9d and xe2x80x9chardnessxe2x80x9d or the like and regulation of crosslinking of polymeric material. The most convenient form allowing gradation of properties is that of a carbon skeleton which may be varied in length. The substituent according to the invention is also normally linked to the olefin by an electron withdrawing group, for reasons of ease of synthesis and the like. Other linking groups may be envisaged such as simple hydrocarbon, phenyl, or alkoxyl (electron donating), whereby the process of the invention may however be carried out with use of any combination of mono and difunctional monomer as hereinafter defined
Reference herein to a monofunctional monomer, hereinafter CnM, and a difunctional monomer, hereinafter CmD, is to compounds comprising respectively one and two strained (poly)cyclic olefin functional units.
The cyclic olefin is preferably a monocyclic olefin, more preferably norbornene, substituted in the 5 and/or 6 positions by exo- and/or endo-normally electron withdrawing group(s) and property modulating tail Y and spacer X as hereinbefore defined.
Preferably an electron withdrawing group is a carbonyl group.
Preferably the monofunctional and difunctional monomer are of formulae I and II: 
wherein at least one R1 is a group Y and comprises a preferably electron withdrawing group, facilitating ROMP reaction with monomer II, and X comprises a 2, 3 or 4-valent or two 2-valent optionally substituted hydrocarbon spacer group(s) adapted to bridge adjacent crosslinked chains and which provides for controllable uniformity and degree of cross linking, providing controlled modulus and Tg.
Preferably at least one R1 is independently selected from COOR2, CONR2, COR2and the like
in which R2 is selected from straight chain and branched, saturated and unsaturated C1-12 hydrocarbon optionally substituted by one or more hydroxy, halo, aryl, cyclo C1-8 alkyl, bisphenol such as bisphenol A, bisphenol F, phenol, hydroquinone and the like, and optionally including at least one heteroatom such as O, P;
and one or more of the remaining groups R1 may be selected from H, C1-3 alkyl, halo such as F and the like;
or two groups R1 together form a cyclic amide or anhydride xe2x80x94(CH2)p CONR3COxe2x80x94; xe2x80x94(CH2)p COOCOxe2x80x94
in which p is 0-4, and is 0 when the two groups form a fused structure or 1-4 when the two groups form a spiro structure;
R3 is as hereinbefore defined for R2 and is a bridging unit; and
X is a linear or fused bridging moiety as hereinbefore defined.
Preferably X is a linear bridging group xe2x80x94COOR2COOxe2x80x94 wherein R2 is as hereinbefore defined, substituting the cyclic olefin at the 5 positions and the 6 positions are unsubstituted or substituted by H, C1-3 alkyl, halo such as F and the like; or
X is a fused bridging group xe2x80x94(CO)2NR3N(CO)2xe2x80x94 in which xe2x80x94(CO)2 N forms a 5 membered cyclic ring with the 5 and 6 positions of each cyclic olefin, 
and wherein R3 is as hereinbefore defined.
Monomers may be exo-, endo- or a mixture thereof. The process of the invention allows the option to select isomers for desired Tg (endo is stiffer than exo) and % trans isomer in the product. Preferably monomers are exo-, which are generally more reactive, than endo- although resulting in lower product Tg.
Preferably the process comprises dissolving the difunctional monomer in the monofunctional monomer and adding initiator in monomer solution. The process conditions may be controlled by selection of monomer ratio and isomer type to provide well ordered living polymerisation or otherwise. It is a particular advantage that the process provides substantially complete cure.
The process of the invention provides as polymeric product of the reaction of I and II a crosslinked structure, an example of which is illustrated in FIG. 1, in which the nature (length) of R leads to control of properties within the system from soft thermoset elastomers to hard or rigid thermoset materials.
The polymerisation is suitably carried out in a predetermined ratio of I:II determining cross-link density and Tg. The selection of groups R2, R3 and X as appropriate determines the material as hard or soft and its modulus and Tg.
A preferred ratio of monomer to difunctional monomer I:II is in the range 99:1 to 50:50, preferably 95:5 to 70:30 or 99:1 to 90:10, which may conveniently be expressed as CnM+x% CmD. More preferably x is 1, 2, 2.5, 3, 5, 8, 10, 30 etc, and is preferably 1 for homogeneous cure.
Contacting the monomer of formula II as hereinbefore defined is preferably in the presence of a catalyst comprising the reaction product of a metal oxide or halide and an alkylating agent. Preferred metals are selected from metals of Group VIII of the Periodic Table of the Elements Mo, Ru, Os, Ir, Rh and Re. Preferred is the xe2x80x9cGrubbsxe2x80x9d catalyst. The catalyst may be as described in WO 97/38036, WO 96/20235 or WO 96/16008 as hereinbefore referred, the contents of which are incorporated herein by reference.
In some instances it is however possible to use the commercially known air sensitive catalyst comprising a Molybdate initiator (BFGoodrich) and still obtain the advantages of the novel polymerisation process and products.
Traditional ring opening metathesis catalysts comprising a metal oxide MXn and cocatalyst such as R3Al or EtAlCl2 in combination, optionally with an O-containing promoter such as EtOH or PhOH may also be employed, depending on selection of cyclic olefin substituent.
The catalyst may be in the presence of or include additional catalytic components or catalytic supports. Reaction may be in a suitable inert atmosphere according to choice of catalyst. The catalyst is present in catalytically effective amount, for example in an amount of 10,000:1 eg 4,000:1 monomer:catalyst.
The polymerisation reaction is suitably carried out in substantial absence of any added solvents, the components being mutually compatible. The reaction is carried out at elevated temperature preferably in excess of room temperature up to approximately 200xc2x0 C. preferably in the range of 60xc2x0 C.-140xc2x0 C. or 160xc2x0 C.-200xc2x0 C., depending on preferred Tg, eg 90xc2x0 C.-100xc2x0 C. to give homogeneous cure. Curing is carried out for a suitable period for example approximately 1 hour. Degassing of monomers is preferably carried out prior to reaction, which may be carried out without need for atmosphere control, or may be carried out in an inert atmosphere, depending on choice of catalyst.
The process of the invention is preferably suited for the preparation of elastomers, plastics, composites in any desired form as shaped products, films, coatings and the like. It is a particular advantage of the process of the invention that such compounds may be readily prepared in which polymerisable monofunctional monomers and/or difunctional bridged monomers are selected to allow controlled crosslinking. The process therefore provides a known and a novel route to access whole ranges of new products using known and novel polymerisable monofunctional monomers and/or difunctional bridged monomers.
In a further aspect of the invention there is provided a class of novel monofunctional monomers of the formula Ii as hereinbefore defined for formula I except that when two R1 together form a cyclic amide, R3 is alkyl having 3 or more carbon atoms, but is not phenyl.
In a further aspect of the invention there is provided a class of novel difunctional bridged monomers of the formula IIi as hereinbefore defined for formula II.
Compounds of the formula I, Ii, II and IIi as hereinbefore defined may be obtained commercially or prepared by known means using Diels Alder methodology.
Copolymers may be exo- or endo- or mixtures thereof and are preferably substantially all exo- as hereinbefore described.
Using this methodology compounds of formula I are obtained from reaction of CPD or a precursor thereof (DCPD may be used and cracks in situ at elevated temperature to yield CPD) with a compound of formula IV: 
or of DCPD with a compound of formula V or VI 
to yield the fused cyclic or spiro dianhydride (VII) and conversion with R3NH2 to 5,5xe2x80x2 or 5,6 cyclo substituted products of formula I 
Intermediate compounds of formula IV as hereinbefore defined may be obtained commercially or by known methodology.
Compounds of formula II may be obtained by analogy with the corresponding compound of formula I by reaction of CPD with a compound of formula VIII 
to yield the linear bridged monomer or reaction of the fused dicarboxyanhydride VII above with diamine H2N(CH2)0-12NH2 to yield the fused bridged dicarboxyimide monomer.
Compounds of formula I as hereinbefore defined comprising a poly (1 to 10) cyclic olefin are obtained by interconversion from the corresponding compound of formula I comprising a monocyclic olefin by Diels Alder reaction with CPD 
In a further aspect of the invention there is provided a process for the polymerisation of polymerisable monofunctional monomers of formula (Ii) as hereinbefore defined.
In a further aspect of the invention there is provided a method for selecting a mono and difunctional monomer as hereinbefore defined, comprising determining modulus and chemical properties of desired cross-links, selecting a ratio of mono:di functional monomers determining the degree of cross-linking, for the cross-linking copolymerisation reaction thereof to provide product with desired properties. The present invention provides choice of multiplicity and nature of polymerisable components to control properties of product in the range of thermoplast (polymerisation of Ii or of IIi) through thermoset (copolymerisation of I and II). Selection of substituents and control of monomer molecular weight allow control of malodourous volatiles during the process and from the polymerised product.
In a further aspect of the invention there is provided a method for the preparation of shaped products comprising reaction injection molding (RIM) or resin transfer molding (RTM) using known techniques.
It is a particular advantage of the present invention that RTM may be employed, by virtue of the lowered reactivity and slower rate of reaction of the polymerisation process of the present invention, by virtue of the presence of the functionalised cyclic olefin groups.
Accordingly the method comprises combining separate streams of polymerisable monofunctional monomers and/or difunctional bridged monomers and catalyst (RIM) or premixing (RTM), injecting into a suitable mold and simultaneously or subsequently heating to activate and/or complete the polymerisation reaction.
The method may employ any suitable reinforcement fibres and the like as known in the art. In this case the mold suitably contains the fibres preformed with use of a binder according to known techniques.
In a further aspect of the invention there is provided a shaped product obtained by the method.
Preferably the shaped product is suitable for any of the hereinbefore defined uses and is associated with advantages in terms of properties (modulus, Tg) as hereinbefore defined.
In a further aspect of the invention there is provided a thermoset or thermoplast polymeric product obtained by a method as hereinbefore defined.